Assessment of radiation hazard indices due to naturally occurring long-life radionuclides in the coastal area of Barra de Valizas, Uruguay.

The Uruguayan east coast has several mineral resources, which include black sand ores in the Barra de Valizas-Aguas Dulces area. Cancer in Uruguay shows non-homogeneous geographical distribution, with the highest standardized mortality ratio (SMR) in the northeast and east region, which includes the aforementioned area and the town of Barra de Valizas. The activity concentration of natural radionuclides (226Ra, 232Th and 40 K) in Barra de Valizas´soil was determined by gamma spectrometry in order to evaluate the radiological hazard for inhabitants and tourists. The outdoor annual effective dose (AEDE), excess lifetime cancer risk (ELCR), and annual gonadal dose equivalent (AGDE) were evaluated for inhabitants with a life expectancy of 77.7 years, a 0.2 and 0.5 occupancy factor, and using the conversion coefficients recommended by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The annual effective dose was also evaluated for both summer and fortnight tourists. The radiological hazard indices for Barra de Valizas inhabitants are higher than the worldwide mean and recommended values. This may contribute to Rocha's higher SRM value, although a direct correlation cannot be assured with the epidemiological information currently available. Social, medical and anthropological studies will be carried out in future to provide data and verify this correlation.

Understanding the Crystal Growth of Bismuth Chalcohalide Nanorods through a Self-Sacrificing Template Process: A Comprehensive Study.

Bismuth-based semiconductors are promising candidates for applications in photocatalysis, photodetection, solar cells, etc. BiSI in particular is attracting attention. It has anisotropic optoelectronic properties and comprises relatively abundant elements. However, the synthesis of this ternary compound presents several challenges. Here, we delve into the underlying chemical processes that lead to the crystal growth of BiSI nanorods and optimize a solution-based synthesis. The mechanism of formation of BiSI nanocrystals is the self-sacrifice of Bi2S3 nanostructures, which also act as templates. The crystallographic similarities between the chalcogenide and the chalcohalide allow for the solid state transformation from one to the other. However, there is also a synergy with the I3- species formed in the reaction media needed to obtain BiSI. Our method makes use of a green solvent, avoids complicated media, and drastically reduces the reaction time compared to other methods. The obtained nanorods present a band gap of 1.6 eV, in accordance with the reported values. This work presents insight into the chemistry of bismuth-based semiconductors, while introducing an easy, green, and scalable synthesis of a promising material, which could also be applied to similar compounds and other chalcoiodides, such as SbSI. In addition, the optical properties of the BiSI nanorods show their potential in photovoltaic applications.

Determination of glyphosate and AMPA in freshwater and soil from agroecosystems by 9-fluorenylmethoxycarbonyl chloride derivatization and liquid chromatography - fluorescence detection and tandem mass spectrometry.

The herbicide glyphosate (GLY) and its metabolite aminophosphonic acid (AMPA) are troublesome compounds for analysis in the environment. Here we report a reliable technique for GLY and AMPA determination in freshwater and soils by means of derivatization with 9-fluorenylmethoxycarbonyl chloride (FMOC-Cl) and further liquid chromatography with fluorescence detection (FLD) and tandem mass spectrometry (MS/MS) analysis. Selected experiments were carried out to evaluate selectivity, sensitivity, repeatability, linearity and quantification performance in both matrices.